Cyclohexanone Compositions and Processes for Making Such Compositions

ABSTRACT

Disclosed are novel cyclohexanone compositions, and processes for making such cyclohexanone compositions, from a mixture comprising phenol, cyclohexanone, and cyclohexylbenzene. Such cyclohexanone compositions comprise at least 99 wt % cyclohexanone, at most 0.15 wt % water, and at most 500 wppm combined of certain cyclohexanone impurities selected from the group consisting of: benzene, cyclohexene, pentanal, cyclopentanol, cyclohexanol, and phenol.

PRIORITY CLAIM

This invention claims priority to and the benefit of U.S. Ser. No.62/198,470 filed Jul. 29, 2015, which is incorporated by referenceherein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. Provisional Application Ser. No.62/140,702 filed Mar. 31, 2015; U.S. Provisional Application Ser. No.62/057,919 filed Sep. 30, 2014; and European Application No. 15151424.7filed Jan. 16, 2015, the disclosures of which are fully incorporatedherein by their reference.

FIELD OF THE INVENTION

The present invention relates to processes for making cyclohexanone. Inparticular, the present invention relates to processes for makingcyclohexanone by phenol hydrogenation. The present invention is useful,e.g., in making cyclohexanone from cyclohexylbenzene oxidation andcyclohexylbenzene hydroperoxide cleavage.

BACKGROUND OF THE INVENTION

Cyclohexanone is an important material in the chemical industry and iswidely used in, for example, production of phenolic resins, bisphenol A,ε-caprolactam, adipic acid, and plasticizers. One method for makingcyclohexanone is by hydrogenating phenol.

Currently, a common route for the production of phenol is the Hockprocess. This is a three-step process in which the first step involvesalkylation of benzene with propylene to produce cumene, followed byoxidation of cumene to the corresponding hydroperoxide, and thencleavage of the hydroperoxide to produce equimolar amounts of phenol andacetone. The separated phenol product can then be converted tocyclohexanone by a step of hydrogenation.

It is known from, e.g., U.S. Pat. No. 6,037,513, that cyclohexylbenzenecan be produced by contacting benzene with hydrogen in the presence of abifunctional catalyst comprising a molecular sieve of the MCM-22 typeand at least one hydrogenation metal selected from palladium, ruthenium,nickel, cobalt, and mixtures thereof. This reference also discloses thatthe resultant cyclohexylbenzene can be oxidized to the correspondinghydroperoxide, which can then be cleaved to produce a cleavage mixtureof phenol and cyclohexanone, which, in turn, can be separated to obtainpure, substantially equimolar phenol and cyclohexanone products. Thiscyclohexylbenzene-based process for co-producing phenol andcyclohexanone can be highly efficient in making these two importantindustrial materials. Given the higher commercial value of cyclohexanonethan phenol, it is highly desirable that in this process morecyclohexanone than phenol be produced. While this can be achieved bysubsequently hydrogenating the pure phenol product produced in thisprocess to convert a part or all of the phenol to cyclohexanone, a moreeconomical process and system would be highly desirable.

One solution to making more cyclohexanone than phenol from the abovecyclohexylbenzene-based process is to hydrogenate a mixture containingphenol and cyclohexanone obtained from the cleavage mixture to convertat least a portion of the phenol contained therein to cyclohexanone.However, because the phenol/cyclohexanone mixture invariably containsnon-negligible amounts of (i) catalyst poison component(s) (such asS-containing components) that can poison the hydrogenation catalyst, and(ii) cyclohexylbenzene that can be converted into bicyclohexane in thehydrogenation step, and because hydrogenation of thephenol/cyclohexanone/cyclohexylbenzene mixture can also lead to theformation of cyclohexanol, resulting in yield loss, this process is notwithout challenge.

Some references of potential interest in this regard may include: U.S.Pat. Nos. 3,076,810; 3,322,651; 4,021,490; 4,439,409; 4,826,667;4,954,325; 5,064,507; 5,168,983; 5,236,575; 5,250,277; 5,362,697;6,037,513; 6,077,498; 6,730,625; 6,756,030; 7,199,271; 7,579,506;7,579,511; and 8,921,603. Other references of potential interest includeWIPO Publication Nos. WO 97/17290; WO 2009/128984; WO 2009/131769; WO2009/134514; WO 2010/098916; WO 2012/036820; WO 2012/036822; WO2012/036823; WO 2012/036828; WO 2012/036830; and WO 2014/137624. Furtherreferences of potential interest include EP 0 293 032; EP 0 606 553; andEP 1 575 892.

SUMMARY OF INVENTION

As such, there is a need for an improved process for makingcyclohexanone from a mixture containing phenol, cyclohexanone,cyclohexylbenzene, and catalyst poison component(s). Advantageously,such improved processes as described herein produce cyclohexanonecompositions that are novel, useful and very different from thosetypically produced by conventional methods (e.g., the conventionalproduction of cyclohexanone via hydrogenation of high purity phenol,and/or the oxidation of cyclohexanol, and the like).

In particular, the present invention in some embodiments provides acyclohexanone composition comprising:

(a) at least 99 wt % cyclohexanone, by total weight of the composition;

(b) 0.15 wt % or less water; and

(c) at most 500 wppm combined of one or more cyclohexanone impuritiesselected from the group consisting of: benzene, cyclohexene, pentanal,cyclopentanol, cyclohexanol, and phenol.

In certain of these embodiments, the composition comprises two or more;three or more; or four or more of the aforementioned cyclohexanoneimpurities. Such compounds may, e.g., be trace impurities resulting fromthe particular process by which the cyclohexanone composition isproduced. In particular embodiments, the cyclohexanone composition maycomprise at least 99.9 wt % cyclohexanone. Such compositions furthercomprise at most 0.05 wt % water, and 500 ppm or less combined ofcyclohexanone impurities.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing a process/system for makingcyclohexanone from a first mixture comprising phenol, cyclohexanone andcyclohexylbenzene including a first distillation column T1, ahydrogenation reactor R1, and a cyclohexanone purification column T2.

FIG. 2 is a schematic diagram showing a portion of a process/systemsimilar to the process/system shown in FIG. 1, but comprising modifiedfluid communications between and/or within the first distillation columnT1 and the hydrogenation reactor R1.

FIG. 3 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 and 2, but comprising modified fluidcommunications and/or heat transfer arrangement between and/or withinthe first distillation column T1 and the cyclohexanone purificationcolumn T2.

FIG. 4 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 to 3, but comprising a tubular heatexchanger-type hydrogenation reactor R1, where the hydrogenationreaction occurs primarily in vapor phase.

FIG. 5 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 to 4, but comprising threehydrogenation reactors R3, R5, and R7 connected in series, where thehydrogenation reaction occurs primarily in liquid phase.

FIG. 6 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 to 5, but comprising modified fluidcommunications between and/or within the first distillation column T1and the hydrogenation reactor R1.

FIG. 7 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 to 6, but comprising an anteriorsorbent bed SBa before the first distillation column T1 configured forremoving at least a portion of catalyst poison components from thephenol/cyclohexanone/cyclohexylbenzene feed fed to the firstdistillation column T1 to reduce or prevent catalyst poisoning in thehydrogenation reactor.

FIG. 8 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 to 7, comprising a posterior sorbentbed SBp after the first distillation column T1 configured for removingat least a portion of the S-containing components from thephenol/cyclohexanone/cyclohexylbenzene feed fed to the hydrogenationreactor to reduce or prevent catalyst poisoning in the hydrogenationreactor.

FIG. 9 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 to 8, comprising a sorbent bed T6after the cyclohexanone purification column T2, configured to reduceamounts of impurities (e.g., catalyst poison components) from the finalcyclohexanone product.

DETAILED DESCRIPTION

Various specific embodiments, versions and examples of the inventionwill now be described, including preferred embodiments and definitionsthat are adopted herein for purposes of understanding the claimedinvention. While the following detailed description gives specificpreferred embodiments, those skilled in the art will appreciate thatthese embodiments are exemplary only, and that the invention may bepracticed in other ways. For purposes of determining infringement, thescope of the invention will refer to any one or more of the appendedclaims, including their equivalents, and elements or limitations thatare equivalent to those that are recited. Any reference to the“invention” may refer to one or more, but not necessarily all, of theinventions defined by the claims.

In the present disclosure, a process is described as comprising at leastone “step.” It should be understood that each step is an action oroperation that may be carried out once or multiple times in the process,in a continuous or discontinuous fashion. Unless specified to thecontrary or the context clearly indicates otherwise, each step in aprocess may be conducted sequentially in the order as they are listed,with or without overlapping with one or more other step, or in any otherorder, as the case may be. In addition, one or more or even all stepsmay be conducted simultaneously with regard to the same or differentbatch of material. For example, in a continuous process, while a firststep in a process is being conducted with respect to a raw material justfed into the beginning of the process, a second step may be carried outsimultaneously with respect to an intermediate material resulting fromtreating the raw materials fed into the process at an earlier time inthe first step. Preferably, the steps are conducted in the orderdescribed.

Unless otherwise indicated, all numbers indicating quantities in thepresent disclosure are to be understood as being modified by the term“about” in all instances. It should also be understood that the precisenumerical values used in the specification and claims constitutespecific embodiments. Efforts have been made to ensure the accuracy ofthe data in the examples. However, it should be understood that anymeasured data inherently contain a certain level of error due to thelimitation of the technique and equipment used for making themeasurement.

As used herein, the indefinite article “a” or “an” shall mean “at leastone” unless specified to the contrary or the context clearly indicatesotherwise. Thus, embodiments comprising “a light component” includeembodiments where one, two or more light components exist, unlessspecified to the contrary or the context clearly indicates that only onelight component exists.

A “complex” as used herein means a material formed by identifiedcomponents via chemical bonds, hydrogen bonds, and/or physical forces.

An “operation temperature” of a distillation column means the highesttemperature liquid media inside the column is exposed to during normaloperation. Thus, the operation temperature of a column is typically thetemperature of the liquid media in the reboiler, if the column isequipped with a reboiler.

The term “S-containing component” as used herein includes all compoundscomprising sulfur.

In the present application, sulfur concentration in a material isexpressed in terms of proportion (ppm, weight percentages, and the like)of the weight of elemental sulfur relative to the total weight of thematerial, even though the sulfur may be present in various valenciesother than zero. Sulfuric acid concentration is expressed in terms ofproportion (ppm, weight percentages, and the like) of the weight ofH₂SO₄ relative to the total weight of the material, even though thesulfuric acid may be present in the material in forms other than H₂SO₄.Thus, the sulfuric acid concentration is the total concentration ofH₂SO₄, SO₃, HSO₄ ⁻, and R—HSO₄ in the material.

As used herein, “wt %” means percentage by weight, “vol %” meanspercentage by volume, “mol %” means percentage by mole, “ppm” meansparts per million, and “ppm wt” and “wppm” are used interchangeably tomean parts per million on a weight basis. All “ppm” as used herein areppm by weight unless specified otherwise. All concentrations herein areexpressed on the basis of the total amount of the composition inquestion. Thus, the concentrations of the various components of thefirst mixture are expressed based on the total weight of the firstmixture. All ranges expressed herein should include both end points astwo specific embodiments unless specified or indicated to the contrary.

In the present disclosure, a location “in the vicinity of” an end (topor bottom) of a column means a location within 10% of the top or bottom,respectively, the % being based upon the total height of the column.That is, a location “in the vicinity of the bottom” of a column iswithin the bottom 10% of the column's height, and a location “in thevicinity of the top” of a column is within the top 10% of the column'sheight.

An “upper effluent” as used herein may be at the very top or the side ofa vessel such as a distillation column or a reactor, with or without anadditional effluent above it. Preferably, an upper effluent is drawn ata location in the vicinity of the top of the column. Preferably, anupper effluent is drawn at a location above at least one feed. A “lowereffluent” as used herein is at a location lower than the upper effluent,which may be at the very bottom or the side of a vessel, and if at theside, with or without additional effluent below it. Preferably, a lowereffluent is drawn at a location in the vicinity of the bottom of thecolumn. Preferably, a lower effluent is drawn at a location below atleast one feed. As used herein, a “middle effluent” is an effluentbetween an upper effluent and a lower effluent. The “same level” on adistillation column means a continuous segment of the column with atotal height no more than 5% of the total height of the column.

Nomenclature of elements and groups thereof used herein are pursuant tothe Periodic Table used by the International Union of Pure and AppliedChemistry after 1988. An example of the Periodic Table is shown in theinner page of the front cover of Advanced Inorganic Chemistry, 6^(th)Edition, by F. Albert Cotton et al. (John Wiley & Sons, Inc., 1999).

As used herein, the term “methylcyclopentanone” includes both isomers2-methylcyclopentanone (CAS Registry No. 1120-72-5) and3-methylcyclopentanone (CAS Registry No. 1757-42-2), at any proportionbetween them, unless it is clearly specified to mean only one of thesetwo isomers or the context clearly indicates that is the case. It shouldbe noted that under the conditions of the various steps of the presentprocesses, the two isomers may undergo isomerization reactions to resultin a ratio between them different from that in the raw materialsimmediately before being charged into a vessel such as a distillationcolumn.

As used herein, the generic term “dicyclohexylbenzene” (“DiCHB”)includes, in the aggregate, 1,2-dicyclohexylbenzene,1,3-dicylohexylbenzene, and 1,4-dicyclohexylbenzene, unless clearlyspecified to mean only one or two thereof. The term cyclohexylbenzene,when used in the singular form, means mono substitutedcyclohexylbenzene. As used herein, the term “C12” means compounds having12 carbon atoms, and “C12+ components” means compounds having at least12 carbon atoms. Examples of C12+ components include, among others,cyclohexylbenzene, biphenyl, bicyclohexane, methylcyclopentylbenzene,1,2-biphenylbenzene, 1,3-biphenylbenzene, 1,4-biphenylbenzene,1,2,3-triphenylbenzene, 1,2,4-triphenylbenzene, 1,3,5-triphenylbenzene,and corresponding oxygenates such as alcohols, ketones, acids, andesters derived from these compounds. As used herein, the term “C18”means compounds having 18 carbon atoms, and the term “C18+ components”means compounds having at least 18 carbon atoms. Examples of C18+components include, among others, dicyclohexylbenzenes (“DiCHB,”described above), tricyclohexylbenzenes (“TriCHB,” including all isomersthereof, including 1,2,3-tricyclohexylbenzene,1,2,4-tricyclohexylbenzene, 1,3,5-tricyclohexylbenzene, and mixtures oftwo or more thereof at any proportion). As used herein, the term “C24”means compounds having 24 carbon atoms.

As used herein, the term “light component” means compound having anormal boiling point (i.e., boiling point at a pressure of 101,325 Pa)lower than cyclohexanone. Examples of the light component include, butare not limited to: (i) methylcyclopentanone; (ii) water; (iii)hydrocarbons comprising 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms,including but not limited to linear, branched linear, cyclic,substituted cyclic, alkanes, alkenes, and dienes; (iv) oxygenates suchas alcohols, aldehydes, ketones, carboxylic acids, ethers, and the like,of hydrocarbons; (v) N-containing compounds, such as amines, amides,imides, NO₂-substituted compounds, and the like; (vi) S-containingcompounds, such as sulfides, sulfites, sulfates, sulfones, and the like.It has been found that S-containing compounds, N-containing compounds,dienes, alkenes, cyclic alkenes, and cyclic dienes, and carboxylic acidscomprising 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms can be present in thephenol/cyclohexanone mixture produced by hydroperoxide cleavagereactions described in greater detail below, and they can beparticularly detrimental to the performance of the hydrogenationcatalyst, leading to catalyst poisoning and undesirable, prematurecatalyst performance reduction.

The term “MCM-22 type material” (or “material of the MCM-22 type” or“molecular sieve of the MCM-22 type” or “MCM-22 type zeolite”), as usedherein, includes one or more of:

-   -   molecular sieves made from a common first degree crystalline        building block unit cell, which unit cell has the MWW framework        topology. A unit cell is a spatial arrangement of atoms which if        tiled in three-dimensional space describes the crystal        structure. Such crystal structures are discussed in the “Atlas        of Zeolite Framework Types,” Fifth Edition, 2001, the entire        content of which is incorporated as reference;    -   molecular sieves made from a common second degree building        block, being a 2-dimensional tiling of such MWW framework        topology unit cells, forming a monolayer of one unit cell        thickness, desirably one c-unit cell thickness;    -   molecular sieves made from common second degree building blocks,        being layers of one or more than one unit cell thickness,        wherein the layer of more than one unit cell thickness is made        from stacking, packing, or binding at least two monolayers of        one unit cell thickness. The stacking of such second degree        building blocks can be in a regular fashion, an irregular        fashion, a random fashion, or any combination thereof; and    -   molecular sieves made by any regular or random 2-dimensional or        3-dimensional combination of unit cells having the MWW framework        topology.

Molecular sieves of the MCM-22 type include those molecular sieveshaving an X-ray diffraction pattern including d-spacing maxima at12.4±0.25, 6.9±0.15, 3.57±0.07, and 3.42±0.07 Angstrom. The X-raydiffraction data used to characterize the material are obtained bystandard techniques such as using the K-alpha doublet of copper asincident radiation and a diffractometer equipped with a scintillationcounter and associated computer as the collection system.

Materials of the MCM-22 type include MCM-22 (described in U.S. Pat. No.4,954,325), PSH-3 (described in U.S. Pat. No. 4,439,409), SSZ-25(described in U.S. Pat. No. 4,826,667), ERB-1 (described in EuropeanPatent No. 0293032), ITQ-1 (described in U.S. Pat. No. 6,077,498), ITQ-2(described in International Patent Publication No. WO 97/17290), MCM-36(described in U.S. Pat. No. 5,250,277), MCM-49 (described in U.S. Pat.No. 5,236,575), MCM-56 (described in U.S. Pat. No. 5,362,697), andmixtures thereof. Other molecular sieves, such as UZM-8 (described inU.S. Pat. No. 6,756,030), may be used alone or together with the MCM-22type molecular sieves as well for the purpose of the present disclosure.Desirably, the molecular sieve used in the catalyst of the presentdisclosure is selected from (a) MCM-49; (b) MCM-56; and (c) isotypes ofMCM-49 and MCM-56, such as ITQ-2.

The process and systems for making cyclohexanone disclosed herein can beadvantageously used for making cyclohexanone from any feed mixturecomprising phenol, cyclohexanone and cyclohexylbenzene. While the feedmay be derived from any process or source, it is preferably obtainedfrom the acid cleavage of a mixture comprising cyclohexylbenzenehydroperoxide and cyclohexylbenzene, which, in turn, is preferablyobtained from aerobic oxidation of cyclohexylbenzene, which, in turn, ispreferably obtained from benzene hydroalkylation. Steps of thesepreferred processes are described in detail below.

Supply of Cyclohexylbenzene

The cyclohexylbenzene supplied to the oxidation step can be producedand/or recycled as part of an integrated process for producing phenoland cyclohexanone from benzene. In such an integrated process, benzeneis initially converted to cyclohexylbenzene by any conventionaltechnique, including oxidative coupling of benzene to make biphenylfollowed by hydrogenation of the biphenyl. However, in practice, thecyclohexylbenzene is desirably produced by contacting benzene withhydrogen under hydroalkylation conditions in the presence of ahydroalkylation catalyst whereby benzene undergoes the followingReaction-1 to produce cyclohexylbenzene (CHB):

Alternatively, cyclohexylbenzene can be produced by direct alkylation ofbenzene with cyclohexene in the presence of a solid-acid catalyst suchas molecular sieves in the MCM-22 family according to the followingReaction-2:

Side reactions may occur in Reaction-1 or Reaction-2 to produce somepolyalkylated benzenes, such as dicyclohexylbenzenes (DiCHB),tricyclohexylbenzenes (TriCHB), methylcyclopentylbenzene, unreactedbenzene, cyclohexane, bicyclohexane, biphenyl, and other contaminantsThus, typically, after the reaction, the hydroalkylation reactionproduct mixture is separated by distillation to obtain a C6 fractioncontaining benzene, cyclohexane, a C12 fraction containingcyclohexylbenzene and methylcyclopentylbenzene, and a heavies fractioncontaining, e.g., C18s such as DiCHBs and C24s such as TriCHBs. Theunreacted benzene may be recovered by distillation and recycled to thehydroalkylation or alkylation reactor. The cyclohexane may be sent to adehydrogenation reactor, with or without some of the residual benzene,and with or without co-fed hydrogen, where it is converted to benzeneand hydrogen, which can be recycled to the hydroalkylation/alkylationstep. Depending on the quantity of the heavies fraction, it may bedesirable to either (a) transalkylate the C18s such as DiCHB and C24ssuch as TriCHB with additional benzene or (b) dealkylate the C18s andC24s to maximize the production of the desired monoalkylated species.

Details of feed materials, catalyst used, reaction conditions, andreaction product properties of benzene hydroalkylation, andtransalkylation and dealkylation can be found in, e.g., the followingcopending, co-assigned patent applications: U.S. Provisional PatentApplication Ser. No. 61/972,877, entitled “Process for MakingCyclohexylbenzene and/or Phenol and/or Cyclohexanone;” and filed on Mar.31, 2014; U.S. Provisional Patent Application Ser. No. 62/037,794,entitled “Process and System for Making Cyclohexanone,” and filed onAug. 15, 2014; U.S. Provisional Patent Application Ser. No. 62/037,801,entitled “Process and System for Making Cyclohexanone,” and filed onAug. 15, 2014; U.S. Provisional Patent Application Ser. No. 62/037,814,entitled “Process and System for Making Cyclohexanone,” and filed onAug. 15, 2014; U.S. Provisional Patent Application Ser. No. 62/037,824,entitled “Process and System for Making Cyclohexanone,” and filed onAug. 15, 2014; U.S. Provisional Patent Application Ser. No. 62/057,919,entitled “Process for Making Cyclohexanone,” and filed on Sep. 30, 2014;U.S. Provisional Patent Application Ser. No. 62/057,947, entitled“Process for Making Cyclohexanone,” and filed on Sep. 30, 2014; and U.S.Provisional Patent Application Ser. No. 62/057,980, entitled “Processfor Making Cyclohexanone,” and filed on Sep. 30, 2014, the contents ofall of which are incorporated herein by reference in their entirety.

Oxidation of Cyclohexylbenzene

In the oxidation step, at least a portion of the cyclohexylbenzenecontained in the oxidation feed is converted tocyclohexyl-1-phenyl-1-hydroperoxide, the desired hydroperoxide,according to the following Reaction-3:

The cyclohexylbenzene freshly produced and/or recycled may be purifiedbefore being fed to the oxidation step to remove at least a portion of,among others, methylcyclopentylbenzene, olefins, phenol, acid, and thelike. Such purification may include, e.g., distillation, hydrogenation,caustic wash, and the like.

In exemplary processes, the oxidation step may be accomplished bycontacting an oxygen-containing gas, such as air and various derivativesof air, with the feed comprising cyclohexylbenzene. For example, astream of pure O₂, O₂ diluted by inert gas such as N₂, pure air, orother O₂-containing mixtures can be pumped through thecyclohexylbenzene-containing feed in an oxidation reactor to effect theoxidation.

The oxidation may be conducted in the absence or presence of a catalyst,such as a cyclic imide type catalyst (e.g., N-hydroxyphthalimide).

Details of the feed material, reaction conditions, reactors used,catalyst used, product mixture composition and treatment, and the like,of the oxidation step can be found in, e.g., the following copending,co-assigned patent applications: U.S. Provisional Patent ApplicationSer. No. 61/972,877, entitled “Process for Making Cyclohexylbenzeneand/or Phenol and/or Cyclohexanone;” and filed on Mar. 31, 2014; U.S.Provisional Patent Application Ser. No. 62/037,794, entitled “Processand System for Making Cyclohexanone,” and filed on Aug. 15, 2014; U.S.Provisional Patent Application Ser. No. 62/037,801, entitled “Processand System for Making Cyclohexanone,” and filed on Aug. 15, 2014; U.S.Provisional Patent Application Ser. No. 62/037,814, entitled “Processand System for Making Cyclohexanone,” and filed on Aug. 15, 2014; U.S.Provisional Patent Application Ser. No. 62/037,824, entitled “Processand System for Making Cyclohexanone,” and filed on Aug. 15, 2014; U.S.Provisional Patent Application Ser. No. 62/057,919, entitled “Processfor Making Cyclohexanone,” and filed on Sep. 30, 2014; U.S. ProvisionalPatent Application Ser. No. 62/057,947, entitled “Process for MakingCyclohexanone,” and filed on Sep. 30, 2014; and U.S. Provisional PatentApplication Ser. No. 62/057,980, entitled “Process for MakingCyclohexanone,” and filed on Sep. 30, 2014, the contents of all of whichare incorporated herein by reference in their entirety.

Cleavage Reaction

In the cleavage reaction, at least a portion of thecyclohexyl-1-phenyl-1-hydroperoxide decomposes in the presence of anacid catalyst in high selectivity to cyclohexanone and phenol accordingto the following desired Reaction-4:

The cleavage product mixture may comprise the acid catalyst, phenol,cyclohexanone, cyclohexylbenzene, and contaminants.

The acid catalyst can be at least partially soluble in the cleavagereaction mixture, is stable at a temperature of at least 185° C. and hasa lower volatility (higher normal boiling point) than cyclohexylbenzene.

Feed composition, reaction conditions, catalyst used, product mixturecomposition and treatment thereof, and the like, of this cleavage stepcan be found in, e.g., the following copending, co-assigned patentapplications: U.S. Provisional Patent Application Ser. No. 61/972,877,entitled “Process for Making Cyclohexylbenzene and/or Phenol and/orCyclohexanone;” and filed on Mar. 31, 2014; U.S. Provisional PatentApplication Ser. No. 62/037,794, entitled “Process and System for MakingCyclohexanone,” and filed on Aug. 15, 2014; U.S. Provisional PatentApplication Ser. No. 62/037,801, entitled “Process and System for MakingCyclohexanone,” and filed on Aug. 15, 2014; U.S. Provisional PatentApplication Ser. No. 62/037,814, entitled “Process and System for MakingCyclohexanone,” and filed on Aug. 15, 2014; U.S. Provisional PatentApplication Ser. No. 62/037,824, entitled “Process and System for MakingCyclohexanone,” and filed on Aug. 15, 2014; U.S. Provisional PatentApplication Ser. No. 62/057,919, entitled “Process for MakingCyclohexanone,” and filed on Sep. 30, 2014; U.S. Provisional PatentApplication Ser. No. 62/057,947, entitled “Process for MakingCyclohexanone,” and filed on Sep. 30, 2014; and U.S. Provisional PatentApplication Ser. No. 62/057,980, entitled “Process for MakingCyclohexanone,” and filed on Sep. 30, 2014, the contents of all of whichare incorporated herein by reference in their entirety.

Separation and Purification

A portion of the neutralized cleavage reaction product can then beseparated by methods such as distillation. In one example, in a firstdistillation column after the cleavage reactor, a heavies fractioncomprising heavies (such as amine sulfuric acid complex, which can beregarded as an amine sulfate salt, if an organic amine is used toneutralize at least a portion of the sulfuric acid present in thecleavage reaction product before it is fed into the first distillationcolumn) is obtained at the bottom of the column, a side fractioncomprising cyclohexylbenzene is obtained in the middle section, and anupper fraction comprising cyclohexanone, phenol, methylcyclopentanone,and water is obtained.

The separated cyclohexylbenzene fraction can then be treated and/orpurified before being delivered to the oxidation step. Since thecyclohexylbenzene separated from the cleavage product mixture maycontain phenol and/or olefins such as cyclohexenylbenzenes, the materialmay be subjected to treatment with an aqueous composition comprising abase and/or a hydrogenation step as disclosed in, for example, WO2011/100013A1, the entire contents of which are incorporated herein byreference.

In one example, the fraction comprising phenol, cyclohexanone, and watercan be further separated by simple distillation to obtain an upperfraction comprising primarily cyclohexanone and methylcyclopentanone anda lower fraction comprising primarily phenol, and some cyclohexanone.Cyclohexanone cannot be completely separated from phenol without usingan extractive solvent due to an azeotrope formed between these two.Thus, the upper fraction can be further distillated in a separate columnto obtain a pure cyclohexanone product in the vicinity of the bottom andan impurity fraction in the vicinity of the top comprising primarilymethylcyclopentanone, which can be further purified, if needed, and thenused as a useful industrial material. The lower fraction can be furtherseparated by a step of extractive distillation using an extractivesolvent (e.g., sulfolane, and glycols such as ethylene glycol, propyleneglycol, diethylene glycol, triethylene glycol, and the like) describedin, e.g., co-assigned, co-pending patent applications WO 2013/165656A1and WO 2013/165659, the contents of which are incorporated herein byreference in their entirety. An upper fraction comprising cyclohexanoneand a lower fraction comprising phenol and the extractive solvent can beobtained. In a subsequent distillation column, the lower fraction canthen be separated to obtain an upper fraction comprising a phenolproduct and a lower fraction comprising the extractive solvent.

Where an acid, such as sulfuric acid, is used as the catalyst in thecleavage step, and a liquid amine is used as the neutralizing agent toneutralize at least a portion of the acid before the cleavage productmixture is fed into the first distillation column, the acid will reactwith the amine to form a complex that is fed into the first distillationcolumn as well. It had been hoped that given the high boiling point ofthe complex, it would stay in the bottom fraction of the firstdistillation column, and therefore all sulfur would be removedcompletely from the bottoms of the first distillation column. However,in a very surprising manner, it has been found that sulfur was presentin the fraction comprising cyclohexanone and phenol exiting the firstdistillation column.

Without intending to be bound by a particular theory, it is believedthat the complex between the acid catalyst and the organic amine, ifpresent in the feed to the first distillation column, can decompose atleast partially in the first distillation column, due to the highoperating temperature therein (i.e., the highest temperature the liquidmedia is exposed to in the first distillation column, typically in thevicinity of the bottom of the column and/or in the reboiler) of at least120° C. (even 130° C., 140° C., 150° C., 160° C., 170° C., 180° C., 190°C., 200° C., 210° C., 220° C., 230° C., 240° C., or even 250° C.) isused, necessitated by the separation of cyclohexylbenzene presenttherein at high concentrations (e.g., at least 5 wt %, or 10 wt %, or 15wt %, or 20 wt %, or 25 wt %, or 30 wt %, or 35 wt %, or 40 wt %, or 45wt %, or even 50 wt %, based on the total weight of the cleavage productmixture), which has a very high normal boiling temperature (240° C.,compared to the normal boiling temperature of cumene of 152° C.). Thedecomposition of the complex likely produces, among others, SO₃, whichcan easily travel upwards along the first distillation column to upperlocations, where it can recombine at least partially with water to formH₂SO₄. This operation temperature can be significantly higher than thedistillation temperature the mixture of cumene, phenol, and acetone isexposed to in the first distillation column in the cumene process formaking phenol and acetone.

Thus, the presence of acid, especially strong acid such as SO₃, R—HSO₄,and/or sulfuric acid in the first distillation column, can catalyze manyundesirable side reactions between and among the many components presentin the distillation mixture, leading to the formation of byproducts(including S-containing components) and/or premature malfunction of thedistillation column. Furthermore, at high operation temperature,prolonged exposure to the acid can cause significant corrosion to thecolumn equipment. The acid species can also make their way into thevarious fractions drawn from the different locations of the firstdistillation column, causing different problems in subsequent stepswhere the fractions are further processed. If the acid species and/orS-containing component enter into a down-stream hydrogenation reactor(described below) where phenol is hydrogenated to make additionalcyclohexanone, the hydrogenation catalyst can be easily deactivated.

Therefore, treating the cleavage product mixture before it enters intothe first distillation column using a solid-phase basic materialaccording to the present invention is highly advantageous and desirable.Doing so would reduce or eliminate the presence of acid species in mediainside the first distillation column, avoid undesirable side reactionsand byproducts formed as a result of contact with the acid species,reduce corrosion of the first distillation column caused by the acidspecies and the associated repair and premature replacement, and preventundesirable side reactions and byproduct formation in subsequent steps.

Such basic materials useful for treatment according to such embodiments,advantageously in solid-phase under the operation conditions, can beselected from (i) oxides of alkali metals, alkaline earth metals, andzinc; (ii) hydroxides of alkali metals, alkaline earth metals, and zinc;(iii) carbonates of alkali metals, alkaline earth metals, and zinc; (iv)bicarbonates of alkali metals, alkaline earth metals, and zinc; (v)complexes of two or more of (i), (ii), (iii), and (iv); (vi) solidamines; (vii) ion-exchange resins; and (viii) mixtures and combinationsof two or more of (i), (ii), (iii), (iv), (v), (vi), and (vii). Oxides,hydroxides, carbonates and bicarbonates of alkali and alkaline earthmetals and zinc can react with acid to form salts thereof, whichpreferably, are also in solid-phase under the operation conditions.Preferably, an ion exchange resin is used. Such ion exchange resinpreferably comprise groups on the surface thereof capable of adsorbingand/or binding with protons, SO₃, HSO₄ ⁻, H₂SO₄, complexes of sulfuricacid, and the like. The ion exchange resin can comprise a strong and/ora weak base resin. Weak base resins primarily function as acidadsorbers. These resins are capable of sorbing strong acids with a highcapacity. Strong base anion resins can comprise quarternized amine-basedproducts capable of sorbing both strong and weak acids. Commercialexamples of basic ion exchange resins useful in the present inventioninclude but are not limited to: Amberlyst® A21 and Amberlyst® A26 basicion exchange resins available from Dow Chemical Company. Amberlyst® A26is an example of a strong base, type 1, anionic, macroreticularpolymeric resin. According to Dow Chemical Company, the resin is basedon crosslinked styrene divinylbenzene copolymer, containing quaternaryammonium groups. A26 is generally considered to be a stronger base resinthan A21.

After treatment using a solid-phase base and/or ion exchange resin, bothtotal acid concentration and acid precursor concentration in the feedsupplied to the first distillation column can be exceedingly low (e.g.,50 ppm or less, such as less than or equal to 20, 15, 10, 5, or 1 ppm).Accordingly, the first distillation column can be operated at a highoperation temperature, such as temperatures higher than thedisassociation temperatures of complex materials formed between the acidcatalyst used in the cleavage step, such as sulfuric acid, and thefollowing organic amines: (i) pentane-1,5-diamine; (ii)1-methylhexane-1,5-diamine; (iii) hexane-1,6-diamine; (iv)2-methylpentane-1,5-diamine; (v) ethylene diamine; (vi) propylenediamine; (vii) diethylene triamine; and (viii) triethylene tetramine,without the concern of issues associated with acid produced from thermaldissociation thereof under such high operation temperature.

Separation and Hydrogenation

At least a portion, preferably the entirety, of the neutralized cleavageeffluent (cleavage reaction product), may be separated and aphenol-containing fraction thereof can be hydrogenated to convert aportion of the phenol to cyclohexanone in accordance with the presentinvention.

It has been found that hydrogenation catalyst used for hydrogenatingphenol to make additional quantities of phenol is highly susceptible topoisoning by S-containing components and/or acids in the feed to thehydrogenation reactor, as well as to other catalyst poison componentsthat may be present in the neutralized cleavage effluent. As such, it ishighly desirable that acids and/or S-containing components, as well asother catalyst poison components, are removed from the stream prior tobeing fed into the hydrogenation reactor.

Examples of the separation and hydrogenation process and/or system areillustrated in the attached drawings and described in detail below. Itshould be understood that process and/or systems shown in the schematic,not-to-scale drawings are only for the purpose of illustrating thegeneral material and/or heat flows and general operating principles. Tosimplify illustration and description, some routine components, such aspumps, valves, reboilers, pressure regulators, heat exchangers,recycling loops, condensers, separation drums, sensors, rectifiers,fillers, distributors, stirrers, motors, and the like, are not shown inthe drawings or described herein. One having ordinary skill in the art,in light of the teachings herein, can add those components whereappropriate.

FIGS. 1, 2, 3, 4, 5, 6, and 9 illustrate processes and systems that donot include an anterior or posterior sorbent bed before or after thefirst distillation column for separating cyclohexanone from phenol forthe purpose of poison removal from the hydrogenation feed. Nonetheless,because these drawings show systems and processes on which the presentinvention is based, they are included and described herein.

FIG. 1 is a schematic diagram showing a process/system 101 for makingcyclohexanone from a mixture comprising phenol, cyclohexanone andcyclohexylbenzene including a first distillation column T1 (i.e., thefirst distillation column), a hydrogenation reactor R1, and acyclohexanone purification column T2 (i.e., the second distillationcolumn). Feed 103 from storage S1, comprising phenol, cyclohexanone, andcyclohexylbenzene, is fed into the first distillation column T1.

Feed 103 can be produced by any method. A preferred method is bycleaving a cyclohexylbenzene hydroperoxide in the presence of an acidcatalyst such as sulfuric acid and cyclohexylbenzene as described above.Feed 103 may further comprise impurities other than cyclohexylbenzenesuch as: hydrogenation catalyst poisons; light components (definedabove) such as water, methylcyclopentanone, pentanal, hexanal, benzoicacid, and the like, and heavy components such asmethylcyclopentylbenzene, bicyclohexane, sulfate of an organic amine(such as 1,6-hexamethylenediame, 2-methyl-1,5-pentamethylenediamine,ethylenediamine, propylenediamine, diethylenetriamine, and the like)produced by injecting the amine into the cleavage mixture to neutralizethe liquid acid catalyst used. Feed 103 may further comprise olefinsheavier than cyclohexanone such as phenylcyclohexene isomers,hydroxylcyclohexanone, cyclohexenone, and the like. Thecyclohexylbenzene hydroperoxide may be produced by aerobic oxidation ofcyclohexylbenzene in the presence of a catalyst such as NHPI asdescribed above. The cyclohexylbenzene may be produced byhydroalkylation of benzene in the presence of a hydrogenation/alkylationbi-functional catalyst as described above.

Thus, feed 103 (the first mixture) may comprise, based on the totalweight thereof:

-   -   10 wt % to 90 wt % (such as about 20 wt % to about 30 wt %, or        20 wt % to about 40 wt %) cyclohexanone;    -   10 wt % to 90 wt % (such as about 20 wt % to about 30 wt %, or        20 wt % to about 40 wt %) phenol (further, the ratio of wt %        cyclohexanone to wt % phenol in the feed is preferably from 0.5        to 1.5);    -   0.001 wt % to 90 wt % (preferably 20 wt % to 70 wt %, such as 30        wt % to 60 wt %) cyclohexylbenzene;    -   0.001 wt % to 1 wt % bicyclohexane; and    -   light components (e.g., benzoic acid, and other carboxylic acids        comprising 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms), S-containing        compounds, and N-containing compounds each at a concentration        ranging from about 0.1 ppm to 10,000 ppm, preferably 1 to 5000        ppm.

From the first distillation column T1, a first upper effluent 105comprising a portion of the cyclohexanone and a portion of lightcomponents such as water, methylcyclopentanone, and the like, isproduced in the vicinity of the top of the column T1. Effluent 105 maycomprise, based on the total weight thereof:

-   -   60 wt % to 99.9 wt %, preferably 75 wt % to 95 wt % or 99.9 wt        %, cyclohexanone;    -   0 wt % to 1 wt % of each of phenol, cyclohexylbenzene, and        bicyclohexane;    -   0.001 wt % to 10 wt % (preferably 0.1 to 5.0 wt %) cyclohexanol;        and    -   light components at a total concentration of 0.001 wt % to 5.0        wt % (preferably 0.001 wt % to 1.0 wt %).

The first upper effluent 105 is then sent to a cyclohexanonepurification column T2, from which a third upper effluent 121 comprisinglight components such as water, methylcyclopentanone, and the like, isproduced at a location in the vicinity of the top of column T2 and thendelivered to storage S5. A second upper effluent 123 comprisingessentially pure cyclohexanone is produced and sent to storage S7. Inthe vicinity of the bottom of column T2, a second lower effluent 125 isproduced and delivered to storage S9. The second lower effluent can be,e.g., a KA oil comprising both cyclohexanone and cyclohexanol. Thus, thesecond upper effluent 123 may comprise, based on the total weightthereof, 95 to 99.9999 wt % (such as 95 wt % to 99.9 wt %)cyclohexanone. The second lower effluent 125 may comprise, based on thetotal weight thereof: 10 wt % to 80 wt % cyclohexanol; and 10 wt % to 80wt % (such as 10 wt % to 40 wt %) cyclohexanone.

The first middle effluent 107 produced from the first distillationcolumn T1 comprises phenol at a concentration higher than in feed 103and higher than in the first upper effluent 105, cyclohexanone at aconcentration lower than in both feed 103 and the first upper effluent105, cyclohexylbenzene at a concentration desirably lower than in feed103 and higher than in the first upper effluent 105, and one or more ofother impurities such as bicyclohexane and cyclohexenone. Thus, effluent107 may comprise, based on total weight thereof:

-   -   1 wt % to 50 wt % (such as 5 wt % to 30 wt %) cyclohexanone;    -   10 wt % to 80 wt % (such as 20 wt % to 80 wt %) phenol, further        wherein the weight ratio of phenol to cyclohexanone is        preferably within the range from 1.0 to 3.0, more preferably        from 2.0 to 3.0;    -   0.001 wt % to 30 wt % (such as 0.001 wt % to 10 wt %)        cyclohexylbenzene;    -   0.001 wt % to 30 wt % (such as 0.001 wt % to 25 wt %)        bicyclohexane;    -   0.01 wt % to 30 wt % (such as 0.01 wt % to 5 wt %) cyclohexanol;        and    -   light components (e.g., benzoic acid, and other organic acid        comprising 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms), S-containing        compounds, and N-containing compounds each at a concentration of        0 wppm to 5000 wppm, preferably 0 wppm to 1000 wppm, such as 1        ppm to 1000 ppm.

Preferably, effluent 107 is essentially free of catalyst poisoncomponents, including S-containing components, that may poison thehydrogenation catalyst used in the hydrogenation reactor(s) R1. However,depending on the quality of feed 103, effluent 107 may comprise catalystpoison components (such as S-containing components) at concentrationscapable of leading to poisoning of the hydrogenation catalyst, asdiscussed above. In such case, embodiments according to the processesand systems illustrated in FIGS. 7 and 8 and described in detail belowmay be advantageously used to reduce the catalyst poison components(including S-containing components) from effluent 107 before it is fedinto the hydrogenation reactor as the whole or a portion of thehydrogenation feed.

Otherwise, effluent 107, if containing catalyst poison components atacceptably low concentration(s), can be directly delivered to ahydrogenation reactor R1, where the effluent 107 is mixed with ahydrogen gas feed 112 comprising fresh make-up hydrogen stream 111 fromstorage S3 and recycle hydrogen 117. The phenol contained in feed 107and hydrogen reacts with each other in the presence of a catalyst bed113 inside reactor R1 to produce cyclohexanone. Some of thecyclohexanone inside the reactor R1 reacts with hydrogen in the presenceof the catalyst bed 113 as well to produce cyclohexanol. In theexemplary process shown in FIG. 1, surplus hydrogen is fed into reactorR1. It is contemplated that a second phenol-containing stream (notshown), separate from and independent of effluent 107, may be fed intothe hydrogenation reactor R1. Such additional feed can advantageouslycontain 50 wt % to 100 wt % phenol. Preferably, the secondphenol-containing stream comprises substantially pure phenol produced byany process, such as the conventional cumene process, coal-basedprocesses, and the like.

The total hydrogenation feed, including stream 107 and optionaladditional streams, delivered to the hydrogenation reactor R1, ifblended together before being fed into R1, may have an overallcomposition comprising, based on the total weight of the hydrogen feedstream 107 and optional additional streams:

-   -   0.1 to 50 wt % cyclohexanone (such as 0.1 to 50 wt %, more        particularly 10 wt % to 50 wt %, even more particularly 20 wt %        to 45 wt %);    -   10 to 99 wt % phenol (such as 30 to 95, or 40 to 85 wt %); and    -   0.001 to 30 wt % of each of cyclohexylbenzene and bicyclohexane        (such as 0.1 wt % to 25 wt %, preferably 1 wt % to 20 wt %        each).

In the hydrogenation reaction zone, the following reactions can takeplace, resulting in an increase of concentrations of cyclohexanone,cyclohexanol, and bicyclohexane, and a decrease of concentrations ofphenol, cyclohexanone, and cyclohexylbenzene:

Cyclohexanone may hydrogenate to make cyclohexanol in the hydrogenationreactor R1. Because the net effect of the reaction is an overallincrease of cyclohexanone concentration, this reaction is not includedin the above paragraph. Nonetheless, cyclohexanone can engage incompetition against phenol for hydrogen, which should be reduced orinhibited.

The total amount of hydrogen, including fresh, make-up hydrogen andrecycled hydrogen, fed into the reactor R1, and the total amount ofphenol fed into the hydrogenation reaction zone desirably exhibit ahydrogen to phenol molar ratio falling within the range of 1:1 to 10:1,preferably within the range of 1:1 to 5:1. While a higher R(H2/phol)ratio can result in higher overall conversion of phenol, it tends toresult in higher conversion of cyclohexanone, higher selectivity ofphenol to cyclohexanol, and higher conversion of cyclohexylbenzene, aswell. Therefore, it is generally desirable that in the hydrogenationreactor R1, the reaction conditions, including but not limited totemperature, pressure, and R(H2/phol) ratio, and catalysts, are chosensuch that the overall conversion of phenol is not too high.

The hydrogenation reactions take place in the presence of ahydrogenation catalyst. The hydrogenation catalyst may comprise ahydrogenation metal performing a hydrogenation function supported on asupport material. The hydrogenation metal can be, e.g., Fe, Co, Ni, Ru,Rh, Pd, Ag, Re, Os, Ir, and Pt, and mixtures and combinations of one ormore thereof. The support material can be advantageously an inorganicmaterial, such as oxides, glasses, ceramics, molecular sieves, and thelike. For example, the support material can be activated carbon, Al₂O₃,Ga₂O₃, SiO₂, GeO₂, SnO, SnO₂, TiO₂, ZrO₂, Sc₂O₃, Y₂O₃, alkali metaloxides, alkaline earth metal oxides, and mixtures, combinations,complexes, and compounds thereof. The concentration of the hydrogenationmetal can be, e.g., in a range from Cm1 wt % to Cm2 wt %, based on thetotal weight of the catalyst, where Cm1 and Cm2 can be, independently:0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0,4.5, 5.0, as long as Cm1<Cm2.

Without intending to be bound by any particular theory, it is believedthat the above hydrogenation reactions occur quickly in the presence ofthe hydrogenation metal. Therefore, it is highly desirable that thehydrogenation metal is preferentially distributed in the outer rim ofthe catalyst particles, i.e., the concentration of the hydrogenationmetal in the catalyst particle surface layer is higher than in the corethereof. Such rimmed catalyst can reduce the overall hydrogenation metalloading, reducing cost thereof, especially if the hydrogenation metalcomprises a precious metal such as Pt, Pd, Ir, Rh, and the like. The lowconcentration of hydrogenation metal in the core of the catalystparticle also leads to a lower chance of hydrogenation of cyclohexanone,which may diffuse from the surface to the core of the catalystparticles, resulting in higher selectivity of cyclohexanone in theoverall process.

Certain light components, such as organic acids (e.g., formic acid,acetic acid, propanoic acid, linear, linear branched and cycliccarboxylic acids comprising 5, 6, 7, or 8 carbon atoms such as benzoicacid), N-containing compounds (e.g., amines, imides, amides,NO₂-substituted organic compounds), and S-containing compounds (e.g.,sulfides, sulfites, sulfates, sulfones, SO₃, SO₂), if contained in thereaction mixture in the hydrogenation reactor and allowed to contact thehydrogenation metal under the hydrogenation reaction conditions,poisoning of the hydrogenation catalyst can occur, leading to reductionof performance or premature failure of the catalyst. To avoid catalystpoisoning, it is highly desirable that the hydrogenation feed comprisessuch catalyst poison components at low concentrations described above.

It is believed that the catalyst surface can have different degrees ofadsorption affinity to the different components in the reaction mediasuch as phenol, cyclohexanone, cyclohexanol, cyclohexenone,cyclohexylbenzene, and bicyclohexane. It is highly desired that thecatalyst surface has higher adsorption affinity to phenol than tocyclohexanone and cyclohexylbenzene. Such higher phenol adsorptionaffinity will give phenol competitive advantages in the reactions,resulting in higher selectivity to cyclohexanone, lower selectivity ofcyclohexanol, and lower conversion of cyclohexylbenzene, which are alldesired in a process designed for making cyclohexanone. In addition, inorder to favor the conversion of phenol to cyclohexanone over theconversion of cyclohexylbenzene to bicyclohexane and the conversion ofcyclohexanone to cyclohexanol, it is highly desired that the phenolconcentration in the reaction medium in the hydrogenation reactor R1 isrelatively high, so that phenol molecules occupy most of the activecatalyst surface area. Therefore, it is desired that the overallconversion of phenol in the reactor R1 is relatively low.

As such, it is desired that in the hydrogenation reactor R1, any one ormore of the following conditions is met:

-   -   (i) 30%≤conversion of phenol≤95%;    -   (ii) 0.1%≤conversion of cyclohexylbenzene≤20%;    -   (iii) 80%≤selectivity of phenol to cyclohexanone        conversion≤99.9%; and    -   (iv) 0.1%≤selectivity of phenol to cyclohexanol conversion≤20%.

The feed(s) to the hydrogenation reactor R1 may further comprise 0.01 wt% to 5 wt % cyclohexenone. It is highly desired that the conversion ofcyclohexenone in the reactor R1 is within the range from 85 to 100%.Thus, a great majority of the cyclohexenone contained in the feed(s) isconverted into cyclohexanone in the hydrogenation reactor R1.

At the bottom of reactor R1, a hydrogenation reaction product stream 115comprising phenol at a concentration lower than in stream 107,cyclohexanone at a concentration higher than in stream 107,cyclohexylbenzene, bicyclohexane, and surplus hydrogen is taken. Stream115 may comprise, based on the total weight thereof:

-   -   20 wt % to 90 wt % (such as 30 wt % or 50 wt % to 90 wt %)        Cyclohexanone;    -   1 wt % to 50 wt % (such as 1 wt % to 15 or 20 wt %) Phenol;    -   0.001 wt % to 30 wt % (such as 0.001 wt % to 15 wt % or 20 wt %)        cyclohexylbenzene;    -   0.001 wt % to 30 wt % (such as 0.001 wt % to 10 wt % or 15 wt %)        bicyclohexane; and    -   0.01 wt % to 10 wt % (such as 0.01 wt % to 5 wt %) cyclohexanol.

Stream 115 is then delivered to a separation drum D1, where a vaporphase comprising a majority of the surplus hydrogen and a liquid phaseis obtained. The vapor phase can be recycled as stream 117 to reactor R1as part of the hydrogen supply, and the liquid phase 119 is recycled tothe first distillation column T1 at one or more side locations on columnT1, at least one of which is above the location where the first middleeffluent 107 is taken, but below the location where the first uppereffluent 105 is taken.

The first bottom effluent 109 obtained from the first distillationcolumn T1 comprises primarily heavy components such ascyclohexylbenzene, bicyclohexane, amine salts mentioned above, C18+, C12oxygenates, and C18+ oxygenates. This fraction is delivered to a heaviesdistillation column T3 (the third distillation column), from which afourth upper effluent 127 desirably comprising cyclohexylbenzene at aconcentration higher than C31 80% and a lower effluent 129 are produced.Effluent 127 may be delivered to storage S11 and effluent 129 to storageS13. Effluent 127 may further comprise olefins, primarilyphenylcyclohexene isomers, at a non-negligible amount. It may bedesirable to subject effluent 127 to hydrogenation to reduce olefinconcentrations, and subsequently recycle the hydrogenated effluent 127to an earlier step such as cyclohexylbenzene oxidation to convert atleast a portion of it to cyclohexylbenzene hydroperoxide, such that theoverall yield of the process is improved.

FIG. 2 is a schematic diagram showing a portion of a process/systemsimilar to the process/system shown in FIG. 1, but comprising modifiedfluid communications between and/or within the first distillation columnT1 and the hydrogenation reactor R1. In this figure, the hydrogenationreaction product 115 comprises residual hydrogen, as in the exampleshown in FIG. 1. Effluent 115 is first delivered into separation drumD1, where a hydrogen-rich vapor stream 117 a is obtained, compressed bya compressor 118, and then delivered to reactor R1 as a stream 117 btogether with fresh, make-up hydrogen stream 111 into reactor R1. Aliquid stream 119 is obtained from separation drum D1, then divided intomultiple streams (two recycle streams 119 a and 119 b shown in FIG. 2),recycled to two different locations on the side of column T1, one belowthe location where the first middle effluent 107 is taken (shown atapproximately the same level as feed 103), and the other above thelocation where the first middle effluent 107 is drawn. This modifiedrecycle fluid communication between the hydrogenation reactor R1 and thefirst distillation column T1 compared to FIG. 1 has surprisingadvantages. It was found that where the recycle liquid stream 119 is fedto one location only, such as at a location above the first middleeffluent 107, bicyclohexane is continuously produced in reactor R1 fromthe cyclohexylbenzene in stream 107, and then steadily accumulates incolumn T1 to such high concentration that a separate phase can form,interfering with effective product separation in column T1. On the otherhand, where the recycle stream 119 is recycled back to column T1 atmultiple locations on T1 (as shown in FIG. 2), the probability offorming a separate bicyclohexane phase inside T1 is drastically reducedor eliminated. Such a configuration, then, may substantially reduce thepresence of impurities such as bicyclohexane in the final cyclohexanoneproduct.

FIG. 3 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1 and 2 comprising modified fluidcommunications and/or heat transfer arrangement between and/or withinthe first distillation column T1 and the cyclohexanone purificationcolumn T2. In this figure, the hydrogenation reactor R1 and itsperipheral equipment are not shown. In this figure, the first middleeffluent 107 drawn from column T1 is divided into multiple streams (twostreams 107 a and 107 b shown), one of which (107 a) is delivered to thehydrogenation reactor R1 (not shown) as hydrogenation feed, and theother (107 b) to a heat exchanger 131 in fluid and thermal communicationwith the cyclohexanone purification column T2. In this figure, thebottom stream 125 (e.g., comprising a mixture of cyclohexanone andcyclohexanol) from column T2 is divided into three streams: stream 135which passes through heat exchanger 131 and is heated by stream 107 b;stream 139 which is heated by a heat exchanger 141 and then recycled tocolumn T2; and stream 145, which is delivered to storage S9 via pump147. Stream 107 b becomes a cooler stream 133 after passing through heatexchanger 131, and is then subsequently recycled to first distillationcolumn T1 at one or more locations, at least one of which is locatedabove the location where the first middle effluent 107 is drawn. A heatmanagement scheme as illustrated in FIG. 3 can significantly improve theenergy efficiency of the overall process and system.

FIG. 4 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1-3, but comprising a tubular heatexchanger-type hydrogenation reactor. This figure illustrates an examplewhere the hydrogenation reactor R1 operates under hydrogenationconditions such that a majority of the phenol and/or cyclohexylbenzenepresent in the reaction media inside the reactor R1 are in vapor phase.In this figure, the first middle effluent 107 taken from the firstdistillation column T1 is first combined with hydrogen feeds (includingfresh make-up hydrogen stream 111 and recycle hydrogen stream 117 b),heated by a heat exchanger 153 and then delivered to a tubularheat-exchanger type hydrogenation reaction R1 having hydrogenationcatalyst installed inside the tubes 157. A stream of cooling media 159such as cold water supplied from storage S11 passes through the shell ofthe exchanger/reactor R1 and exits the reactor R1 as a warm stream 161and is then delivered to storage S13, thereby a significant amount ofheat released from phenol hydrogenation reaction is carried away,maintaining the temperature inside the reactor R1 in a range from 140°C. to 300° C. (preferably about 220° C. to about 260° C., such as about240° C.), and an absolute pressure inside the reactor R1 in a range from100 kPa to 400 kPa (preferably about 180 kPa to about 220 kPa, such asabout 200 kPa). Alternatively, the cooling medium may comprise at leasta portion of the hydrogenation feed in liquid phase, such that at leasta portion of the feed is vaporized, and at least a portion of the vaporfeed is then fed to the hydrogenation reactor R1.

Because heat transfer of a vapor phase is not as efficient as a liquidphase, and the phenol hydrogenation reaction is highly exothermic, it ishighly desired that heat transfer is carefully managed in such vaporphase hydrogenation reactor. Other types of reactors suitable for aliquid phase reaction can be used as well. For example, fixed-bedreactors configured to have intercooling capability and/or quenchingoptions, so that the heat generated in the reaction can be taken awaysufficiently quickly to maintain the reaction media in a desirabletemperature range.

FIG. 5 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1-4, but comprising three fixed bedhydrogenation reactors R3, R5, and R7 connected in series. This figureillustrates an example where the hydrogenation reactors operate underhydrogenation conditions such that a majority of the phenol and/orcyclohexylbenzene present in the reaction media inside the reactors R3,R5, and R7 are in liquid phase. In this figure, the first middleeffluent 107 taken from the first distillation column T1 is firstcombined with hydrogen feeds (including fresh make-up hydrogen stream111 and recycle hydrogen stream 117 b) to form a feed stream 151, thenheated by a heat exchanger 153, and then delivered as stream 155 to afirst hydrogenation reactor R3 having a catalyst bed 167 inside. Aportion of the phenol is converted to cyclohexanone in reactor R3,releasing a moderate amount of heat raising the temperature of thereaction media. Effluent 169 exiting reactor R3 is then cooled down byheat exchanger 171, and then delivered into a second fixed bed reactorR5 having a catalyst bed 175 inside. A portion of the phenol containedin the reaction media is converted to cyclohexanone in reactor R5,releasing a moderate amount of heat raising the temperature inside thereactor R5. Effluent 177 exiting reactor R5 is then cooled down by heatexchanger 179, and then delivered to a third fixed bed hydrogenationreactor R7 having a catalyst bed 183 inside. A portion of the phenolcontained in the reaction media is converted to cyclohexanone in reactorR7, releasing a moderate amount of heat raising the temperature insidethe reactor R7. Effluent 185 exiting reactor R7 is then cooled down byheat exchanger 187, and delivered to drum D1, where a vapor phase 117 aand a liquid phase 119 are obtained. By using multiple reactors in thehydrogenation reaction zone, and the use of heat exchangers betweenadjacent reactors and after each reactor, temperatures inside thereactors R3, R5, and R7 are each independently maintained in a rangefrom 140° C. to 300° C. (preferably about 220° C. to about 260° C., suchas about 240° C.), and the absolute pressures inside reactors R3, R5,and R7 are each independently maintained in a range from 375 kPa to 1200kPa (preferably about 1000 to about 1200 kPa, such as about 1134 kPa).In general, higher temperature favors the production of cyclohexanolover cyclohexanone. Thus, it is highly desirable that the hydrogenationis conducted at a temperature no higher than 220° C.

FIG. 6 is a schematic diagram showing a portion of a process/systemsimilar to the process/system shown in FIGS. 1-5, but comprisingmodified fluid communications between and/or within the firstdistillation column T1 and the hydrogenation reactor R1. In this figure,two middle effluents, including a first middle effluent 107 a and asecond middle effluent 107 b, are drawn from the side of the firstdistillation column T1. The two effluents 107 a and 107 b have differingcompositions, and are combined to form a feed 107, which is thencombined with hydrogen feed streams 111 and 117 b and delivered to thehydrogenation reactor(s). Drawing two middle effluents with differentcompositions at different locations have unexpected technicaladvantages. It was found that if only one middle effluent is drawn froma single location on column T1, certain undesirable components, such ashydroxycyclohexanone(s), can accumulate in column T1. It is believedthat hydroxycyclohexanone(s) can undergo dehydration to formcyclohexenone, which can cause fouling inside column T1. By drawingmiddle effluents at different height locations on the column, one caneffectively reduce the accumulation of such undesirable components andthe probability of fouling inside the column.

FIG. 7 is a schematic diagram showing a portion of an exemplaryprocess/system of the present disclosure similar to those shown in FIGS.1-6, but comprising an anterior sorbent bed SBa before the firstdistillation column T1 configured for removing at least a portion of theS-containing components and/or the light components (especially catalystpoison components) from a crude feed (crude mixture) to reduce orprevent catalyst poisoning in the hydrogenation reactor. A preferredanterior sorbent bed SBa according to some embodiments comprises anAmberlyst® A21 sorbent bed, although other sorbent beds (e.g., astronger basic ion exchange resin such as Amberlyst® A26) could be usedin addition or instead. A crude mixture feed stream 102 is first passedthrough the sorbent bed SBa, in which a basic solid-phase sorbentmaterial described above is installed. Alternatively, where the totalconcentration of catalyst poison components (e.g., the S-containingcomponents and other light components capable of poisoning thehydrogenation catalyst) in the crude mixture stream 102 is exceedinglyhigh, an anterior distillation column (not shown) may be used before theanterior sorbent bed SBa, so as to remove a portion of the catalystpoison components from the first mixture fed into the first distillationcolumn Instead or in addition, one or more additional anterior sorbentbeds (also not shown in FIG. 7) may be utilized, any one or more ofwhich may be the same or different from the anterior sorbent bed SBa.For instance, a suitable additional anterior sorbent bed could comprisea nickel sorbent, an ion exchange resin, and/or an activated carbon bed.Such sorbents may remove one or more S-containing components, and/orother catalyst poison components, and/or color bodies (i.e., impuritiesthat impart some coloration to the feed stream 102). Desirably, upontreatment by the anterior sorbent bed SBa (and/or the optional anteriordistillation column, and/or any one or more additional anterior sorbentbeds), concentrations of catalyst poison components capable of poisoningthe hydrogenation catalyst is reduced significantly in effluent 107compared to in feed 102. Thus, in the embodiment shown in FIG. 7, theratio of concentration of catalyst poison components in the effluent 107to the concentration of said components in the feed 102 is within therange of about 0.001 to 0.5, preferably about 0.001 to about 0.1, suchas 0.001 to 0.1. For instance, the ratio of concentration of sulfuricacid in feed 102 to concentration of sulfuric acid in effluent 107 ispreferably within the range of about 0.001 to about 0.1, such as 0.001to 0.1.

FIG. 8 shows an alternative to the configuration of FIG. 7. In thisfigure, instead of placing an anterior sorbent bed SBa before the firstdistillation column T1, a posterior sorbent bed SBp is placed behindcolumn T1, which receives the first middle effluent 107 as a feed,produces a treated stream 195 depleted or low in S-containing componentsand/or any one or more other catalyst poison components such as lightacids. A preferred posterior sorbent bed SBp comprises an Amberlyst® A26ion exchange resin, referenced previously, although other sorbent beds,such as other ion exchange resins (e.g., Amberlyst® A21) may be used.The treated stream 195 is then delivered to the hydrogenation reactor asa portion or all of the hydrogenation feed 151 together with hydrogenfeeds 111 and 117 b. Alternatively, where the total concentration of thecatalyst poison components (such as the S-containing components and/orother poisons) in the first middle effluent 107 is exceedingly high(and/or where concentrations of other impurities with differentvolatilities than phenol and cyclohexanone in the first middle effluent107 are exceedingly high) a posterior distillation column (not shown)may be installed before or after (that is, upstream of or downstream of,respectively) the sorbent bed SBp, and effluent 107 may be treated byboth the posterior distillation column and the posterior sorbent bed SBpbefore being fed to the hydrogenation reactor R1 as at least a portionof the hydrogenation feed. Such a posterior distillation column may beused to remove either light or heavy components relative to the phenoland cyclohexanone in the first middle effluent 107.

Further, other treatment options may be present instead of or inaddition to the posterior distillation column (also not shown). Forexample, one or more additional posterior sorbent beds may be utilized,any one or more of which may be the same or different from the posteriorsorbent bed SBp. Preferably, at least one additional posterior sorbentbed is different from the posterior sorbent bed SBp. For instance, aparticularly suitable additional posterior sorbent bed comprises anickel sorbent. Such a sorbent may remove S-containing components and/orother catalyst poison components from the effluent 107. It may alsoremove color bodies (e.g., trace byproducts that impart some degree ofcoloration to the effluent 107). Alternatively or in addition, at leastone additional posterior sorbent bed may comprise an activated carbonsorbent. Desirably, upon treatment by one or more of (i) the posteriorsorbent bed SBp, (ii) the posterior distillation column, and (iii) oneor more additional posterior sorbent beds, concentrations ofS-containing components capable of poisoning the hydrogenation catalystare reduced significantly in the hydrogenation feed compared to ineffluent 107. Preferably, concentrations of any other impurities,including other catalyst poison components and/or impurities havingdifferent volatilities from phenol and cyclohexanone, are also reduced.For instance, in the embodiment shown in FIG. 8 (employing a posteriorsorbent bed SBp), the ratio of concentration of catalyst poisoncomponents (including S-containing components and other light componentscapable of poisoning the hydrogenation catalyst) in the effluent 107 tothe concentration of said components in the hydrogenation feed is withinthe range of about 0.001 to 0.5, preferably about 0.001 to about 0.1,such as 0.001 to 0.1. For instance, the ratio of concentration ofsulfuric acid in the hydrogenation feed to concentration of sulfuricacid in effluent 107 is preferably within the range of about 0.001 toabout 0.1, such as 0.001 to 0.1.

If necessary, in some embodiments, both (i) the anterior treatmentmechanism described in connection with FIG. 7 (e.g., one or both of theanterior distillation column and the anterior sorbent) and (ii) theposterior treatment mechanism described in connection with FIG. 8 (e.g.,one or more of the posterior distillation column, the posterior sorbentbed, and the one or more additional posterior sorbent beds) may be usedto prevent catalyst poison components (including the S-containingcomponents) from entering into the hydrogenation reactor(s) at anunacceptably high concentration. The anterior and posterior sorbents,and/or the optional additional posterior sorbent(s), can be the same ordifferent, and may each independently be selected from: massive nickel,activated carbon, ion exchange resins (such as strong and weak anionresins which are usually amine based), clay, kaolin, silica sorbents,alumina sorbents, molecular sieves, (i) oxides of alkali metals,alkaline earth metals, and zinc; (ii) hydroxides of alkali metals,alkaline earth metals, and zinc; (iii) carbonates of alkali metals,alkaline earth metals, and zinc; (iv) bicarbonates of alkali metals,alkaline earth metals, and zinc; (v) complexes of two or more of (i),(ii), (iii), and (iv); (vi) solid amines; (vii) ion-exchange resins; and(viii) mixtures and combinations of two or more of (i), (ii), (iii),(iv), (v), (vi), and (vii). The sorbents may remove impurities such ascatalyst poison components (including the S-containing components) byphysical absorption or adsorption, extraction, and/or chemicalreactions. Massive nickel is particularly useful for removingS-containing and N-containing poison components. However, a basic,solid-phase sorbent material such as those described above is preferablefor removing sulfuric acid. A basic ion exchange resin is particularlypreferable for removing acid species and/or S-containing species.

FIG. 9 is a schematic diagram showing a portion of a process/systemsimilar to those shown in FIGS. 1-8 comprising a side stripper column T6after the cyclohexanone purification column T2, configured to reduceamounts of light components from the final cyclohexanone product. Inthis figure, the first upper effluent 105 comprising primarilycyclohexanone and light components obtained from the first distillationcolumn T1 and from the upper anterior stripper effluent, if any, isdelivered to cyclohexanone purification column T2, where three effluentsare obtained: a second upper effluent 121 rich in light components suchas water and methylcyclopentanone and depleted in cyclohexanone andcyclohexanol, a second middle effluent 123 rich in cyclohexanone anddepleted in light components and cyclohexanol, and a second lowereffluent 125 rich in cyclohexanol. Effluent 121 is first cooled down bya heat exchanger 197, then delivered to a separation drum D2 to obtain aliquid phase 199, which is recycled to column T2, and a vapor phase 201,which is cooled again by a heat exchanger 203, and delivered to anotherseparation drum D3 to obtain a liquid phase which is partly recycled asstream 205 to drum D2, and partly delivered to storage S5, and a vaporphase 206 which can be purged. Effluent 123 is delivered to a sidestripper T6 where the following streams are produced: a substantiallypure cyclohexanone stream 211 in the vicinity of the bottom thereof,which is delivered to a storage S7; and a light component stream 209,which is recycled to the column T2 at a location above 123.

Additional post-hydrogenation treatment (e.g., of a phenol hydrogenationreaction effluent such as effluent 127 of FIG. 1) is also contemplatedin some embodiments. For instance, similar to the embodiment of FIG. 9(comprising further treatment by distillation and/or stripping ofcyclohexanone from first distillation column T1), the product effluentfrom phenol hydrogenation (e.g., hydrogenation from reactor R1) may besubjected to one or more distillation procedures. Such additionaldistillation could take place in additional distillation columns, orcould be effected by providing at least a portion of such phenolhydrogenation effluent to one or more of the first distillation columnT1 or the cyclohexanone purification column T2 of the variousembodiments just described. However, in any post-treatment of thecyclohexanone, particularly of a stream comprising the phenolhydrogenation reaction effluent, the stream should preferably not besubjected to temperatures in excess of 280° F. (137.8° C.), as it hasbeen found that subjecting a phenol hydrogenation effluent to suchtemperatures may substantially increase the amount of cyclohexenepresent in the final product. Preferably, the product of any phenolhydrogenation is not subjected to temperatures in excess of 250° F.(121.1° C.), most preferably not in excess of 235° F. (112.8° C.), so asto minimize or avoid the formation of additional cyclohexene that couldbe present in the final product cyclohexanone composition. This includesoperation of a distillation column such that temperature at or below thewithdrawal point of a cyclohexanone-containing stream is in excess ofthe aforementioned temperatures, and further includes operation of areboiler associated with any such distillation column, through which aproduct stream or a portion of a product stream may pass.

Cyclohexanone Compositions

In various embodiments, the methods and/or systems described hereincreate compositions that are rich in cyclohexanone (also referred to ascyclohexanone compositions).

Preferably, the cyclohexanone composition comprises at least 99 wt %cyclohexanone, based on the total weight of the cyclohexanonecomposition. More preferably, the cyclohexanone composition comprises atleast 99.9 wt %, such as at least 99.94 wt %, 99.95, or even 99.99 wt %cyclohexanone.

The cyclohexanone composition may further comprise one or morecyclohexanone impurities selected from the following compounds: benzene,cyclohexene, pentanal, cyclopentanol, cyclohexanol, and phenol. As usedherein, a “cyclohexanone impurity” is any compound other thancyclohexanone or water, which is typically acceptable in commerciallyavailable cyclohexanone compositions in small amounts. In the presentinvention, water is advantageously present in the cyclohexanonecomposition in amounts of 0.15 wt % or less, such as 0.1 wt % or less,or 0.05 wt % or less, based on total weight of the cyclohexanonecomposition. Preferably, the total amount of cyclohexanone impurities is500 wppm or less, more preferably 200 wppm or less, most preferably 150wppm or less, or even 100 wppm or less, each wppm being based upon thetotal weight of the cyclohexanone composition.

The cyclohexanone composition may comprise any one or more, two or more,three or more, or four or more of such cyclohexanone impurities. Inparticular embodiments, the cyclohexanone composition comprises one orboth of pentanal and cyclopentanol. Compositions of such embodiments mayalso or instead comprise one or both of cyclohexene and cyclohexanol.The combined amount of cyclohexanone impurities in such embodiments is200 wppm or less, preferably 100 wppm or less.

In certain embodiments, the cyclohexanone composition may consist ofcyclohexanone, 0.15 wt % or less (preferably 0.1 wt % or less, mostpreferably 0.05 wt % or less) water, and 500 wppm or less (preferably200 wppm or less, most preferably 100 wppm or less) of one or morecyclohexanone impurities. The cyclohexanone impurities in suchembodiments are preferably selected from the group consisting of:benzene, cyclohexene, pentanal, cyclopentanol, cyclohexanol, and phenol.In certain embodiments, the cyclohexanone impurities are selected fromthe group consisting of: cyclohexene, pentanal, cyclopentanol, andcyclohexanol. Such compositions may consist of any one, two, three, orfour of the foregoing impurities. In particular embodiments, theimpurities consist of cyclohexene, pentanal, cyclopentanol, andcyclohexanol. In yet further particular embodiments, the impuritiesconsist of (i) cyclohexene, (ii) cyclopentanol or pentanal, and (iii)cyclohexanol.

With respect to each aforementioned cyclohexanone impurity in thecyclohexanone compositions of various embodiments:

-   -   Benzene may be present in an amount ranging from 0 to 20 wppm.        For instance, benzene may be present at 0 wppm to 5 wppm,        preferably 0 wppm to 2.5 wppm.    -   Cyclohexene may be present in an amount ranging from 0 to 20        wppm. For instance, cyclohexene may be present at 0 wppm to 15        wppm, such as 2.5 wppm to 15, or 5 wppm to 10 wppm.    -   Pentanal may be present in an amount ranging from 0 to 20 wppm,        provided the high end of the range is greater than the low end.        For instance, pentanal may be present at 0 wppm to 10 wppm, such        as 1 wppm to 10 wppm, potentially 3 wppm to 7 wppm.    -   Cyclopentanol may be present in an amount ranging from 0 to 80        wppm. For instance, cyclopentanol may be present at 10 wppm to        50 wppm, such as 15 to 40 wppm, or 20 to 35 wppm.    -   Cyclohexanol may be present in an amount ranging from 0 to 80        wppm. For instance, cyclohexanol may be present at 0 wppm to 40        wppm, such as 10 wppm to 40 wppm, for instance 12 wppm to 30        wppm, or 10 wppm to 20 wppm.

In various embodiments, any one or more of these cyclohexanoneimpurities may have been generated in situ during a process for makingcyclohexanone (i.e., they were not added from an external source). Forinstance, any one or more of the cyclohexanone impurities may have beenformed during the phenol hydrogenation reaction. This is particularlylikely for cyclohexanone impurities such as cyclohexanol, cyclohexene,and water. Additionally, any trace amount of unreacted phenol left overfrom the hydrogenation reaction may remain as a cyclohexanone impurityin some embodiments. Furthermore, in certain embodiments, at least aportion of the cyclohexene may have been produced at least in partduring distillation or other treatment of all or part of the phenolhydrogenation reaction effluent (i.e., the products of hydrogenation ofthe hydrogenation feed comprising cyclohexanone and phenol, such astakes place in R1 of FIG. 1). As already noted, however, such amounts ofcyclohexene may be minimized by avoiding subjecting said all or part ofthe phenol hydrogenation reaction effluent to temperatures in excess of280° F., preferably avoiding temperatures in excess of 250° F., mostpreferably avoiding temperatures in excess of 235° F.

Further, in various embodiments, all or at least part of the pentanaland/or cyclopentanol may be formed either before or after (i.e.,upstream or downstream of, respectively) hydrogenation of thehydrogenation feed comprising cyclohexanone and phenol. For instance, insome embodiments in accordance with FIGS. 1, 7, and/or 8, pentanaland/or cyclopentanol may be formed in the first distillation column T1.In yet other embodiments in accordance with FIGS. 7 and/or 8, pentanaland/or cyclopentanol may be formed in a posterior distillation columnand/or an anterior distillation column used to pre-treat hydrogenationreaction feed. In yet further embodiments, pentanal and/or cyclopentanolmay be formed in any distillation column or other treatment to which allor a portion of the phenol hydrogenation reaction effluent is subjected.

Uses of Cyclohexanone and Phenol

The cyclohexanone composition produced through the processes disclosedherein may be used, for example, as an industrial solvent, as anactivator in oxidation reactions and in the production of adipic acid,cyclohexanone resins, cyclohexanone oxime, caprolactam, and nylons, suchas nylon-6 and nylon-6,6. Thus, further embodiments may includecaprolactam produced using a cyclohexanone composition according to anyof the aforementioned embodiments. Likewise, further embodiments mayinclude nylon produced using a cyclohexanone composition according toany of the aforementioned embodiments. Similarly, methods according tosome embodiments may include producing one or both of caprolactam andnylon using a cyclohexanone composition according to any of theaforementioned embodiments.

The phenol produced through the processes disclosed herein may be used,for example, to produce phenolic resins, bisphenol A, ε-caprolactam,adipic acid, and/or plasticizers.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For this reason, then, reference shouldbe made solely to the appended claims for purposes of determining thetrue scope of the present invention.

The contents of all references cited herein are incorporated byreference in their entirety.

1. A cyclohexanone composition comprising: (a) at least 99 wt %cyclohexanone; (b) 0.15 wt % or less water; (c) 0 to 10 wppm benzene;(d) 5 to 10 wppm cyclohexene; (e) 0 to 10 wppm pentanal; (f) 0 to 50wppm cyclopentanol; and (g) 10 wppm to 40 wppm cyclohexanol; wherein thewt % and wppm are each based upon total weight of the cyclohexanonecomposition.
 2. The cyclohexanone composition of claim 12, comprising atleast 99.9 wt % cyclohexanone and at most 0.05 wt % water, based uponthe total weight of the cyclohexanone composition.
 3. The cyclohexanonecomposition of claim 1, comprising 1 wppm to 10 wppm pentanal, basedupon the total weight of the cyclohexanone composition.
 4. Thecyclohexanone composition of claim 3, comprising 10 wppm to 50 wppmcyclopentanol, based upon the total weight of the cyclohexanonecomposition.
 5. The cyclohexanone composition of claim 1, comprising 10wppm to 50 wppm cyclopentanol, based upon the total weight of thecyclohexanone composition.
 6. The cyclohexanone composition of claim 1,comprising 10 wppm to 20 wppm cyclohexanol.
 7. The cyclohexanonecomposition of claim 1, wherein the cyclohexanone composition consistsof: (a) at least 99 wt % cyclohexanone; (b) 0.15 wt % or less water; (c)0 to 10 wppm benzene; (d) 5 to 10 wppm cyclohexene; (e) 0 to 10 wppmpentanal; (f) 0 to 50 wppm cyclopentanol; and (g) 10 wppm to 40 wppmcyclohexanol; wherein the wt % and wppm are each based upon total weightof the cyclohexanone composition.
 8. The cyclohexanone composition ofclaim 7, wherein the cyclohexanone is present at 99.9 wt % or greater,and further wherein the water is present at 0.05 wt % or less, basedupon the total weight of the cyclohexanone composition.
 9. Thecyclohexanone composition of claim 7, wherein the pentanal is presentwithin the range of 1 to 10 wppm, based upon the total weight of thecyclohexanone composition.
 10. The cyclohexanone composition of claim 7,wherein the cyclopentanol is present within the range of 10 to 50 wppm,based upon the total weight of the cyclohexanone composition.
 11. Thecyclohexanone composition of claim 7, wherein the cyclohexanol ispresent within the range of 10 wppm to 20 wppm, based upon the totalweight of the cyclohexanone composition.
 12. A cyclohexanone compositionconsisting of: (a) at least 99 wt % cyclohexanone; (b) 0.15 wt % or lesswater; and (c) 500 wppm or less combined of one or more cyclohexanoneimpurities; wherein the cyclohexanone impurities comprise pentanal,cyclopentanol, or both; and further wherein the wt % and wppm are eachbased upon total weight of the cyclohexanone composition.
 13. Thecyclohexanone composition of claim 12, wherein the cyclohexanoneimpurities comprise pentanal and cyclopentanol.
 14. The cyclohexanonecomposition of claim 12, wherein the cyclohexanone impurities furthercomprise one or more of: benzene, cyclohexene, cyclohexanol, and phenol.15. The cyclohexanone composition of claim 12, wherein the cyclohexanoneimpurities consist of: cyclohexene, pentanal, cyclopentanol, andcyclohexanol.
 16. The cyclohexanone composition of claim 12, comprisingat least 99.9 wt % cyclohexanone, at most 0.05 wt % water, and 200 wppmor less combined of the one or more cyclohexanone impurities.